(a) Technical Field
Embodiments of the present invention relate to a liquid crystal display. More particularly, the present invention relates to a vertical alignment (VA) mode liquid crystal display with an increased transmittance.
(b) Description of the Related Art
A liquid crystal display (LCD) is one of the most widely used flat panel displays (FPD), and it is composed of two display panels on which field generating electrodes such as pixel electrodes and a common electrode are formed, and a liquid crystal layer interposed between the two display panels. A voltage is applied to the field generating electrodes to generate an electric field on the liquid crystal layer, and the orientation of liquid crystal molecules of the liquid crystal layer is determined and the polarization of incident light is controlled through the generated electric field to display an image.
Among the LCDs, a vertical alignment (VA) mode LCD, which aligns LC molecules such that their long axes are perpendicular to the panels in the absence of an electric field, is spotlighted because of its high contrast ratio and wide reference viewing angle.
In the vertical alignment (VA) mode liquid crystal display, to obtain the wide viewing angle, a plurality of domains in which the alignment direction of the liquid crystal molecules are different may be formed in one pixel.
As one example of forming the plurality of domains in one pixel, there is a method of forming cutouts of minute slits in the field generating electrodes. In this method, the plurality of domains may be formed by aligning the liquid crystal molecules vertically with respect to a fringe field generated between edges of the cutouts and the field generating electrodes facing the edges.
As examples, liquid crystal displays having a domain-forming member include a VA mode liquid crystal display having domain-forming members formed at both of the upper and lower substrates, and a patternless VA mode liquid crystal display having minute patterns formed only at a lower substrate without forming patterns on an upper substrate. A display area is sectored into a plurality of domains by the domain-forming members, and liquid crystal molecules in each domain are inclined in the same direction.
Recently, a method for providing a pretilt to the liquid crystal molecules in the absence of an electric field has been developed to improve the response speed of the liquid crystal while realizing a wide viewing angle. For the liquid crystal molecules to have the pretilt of the various directions, alignment layers having various alignment directions may be used, or an alignment aid is added and is hardened to pretilt the liquid crystal molecules of the liquid crystal layer after applying the electric field to the liquid crystal layer. The alignment aid hardened by heat or light such as ultraviolet rays may provide the pretilt to the liquid crystal molecules in a predetermined direction. To generate the electric field to the liquid crystal layer, the voltage is respectively applied to the field generating electrodes.
However, to manufacturing the liquid crystal display including the alignment aid for the pretilt, the precursor of the alignment aid is added to a liquid crystal layer or an alignment layer, and the hardening process of ultraviolet rays must be added such that a new process line is required and an increase in cost is inevitable. Accordingly, the manufacturing cost of the liquid crystal display is increased, the additional manufacturing equipment is required, and the manufacturing process is complicated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.